1. Field of the Invention
The present invention relates to a top-loading precision balance with a draft protection device which includes several walls which are connected to each other at the edges thereof and a cover which closes the opening defined at the top of the walls and is pivotally fastened by means of a horizontally extending hinge.
2. Description of the Related Art
Precision balances with a draft protection device of the above-described type are known in the art. Thus, Swiss Patent 677,029 describes a draft protection device whose side walls are connected to each other at the edges thereof by means of section bars and which can be closed at the top by means of a cover hinged to one of the side walls. The known draft protection device rests as a result of its own weight on the balance housing and is not otherwise fastened to the balance housing. The cover is connected in a simple manner by means of a hinge to the rear side wall of the draft protection device. In order to enable viewing through the draft protection device, the side walls as well as the cover are of glass. The cover projects only slightly beyond the side walls and is relatively heavy. Thus, since the cover must be opened each time the balance is loaded, the cover may slide out of the hand of the operator by incorrectly handling the cover and, consequently, the cover may drop onto the upper edges of the sidewalls. This results in the danger that the glass cover may break. Another disadvantage of this draft protection device is the fact that, because of the high weight of the cover, frequent opening and closing of the cover in the case of a large series of weighing procedures will lead to fatigue of the person operating the balance.
Another disadvantage of the known draft protection device is that the draft protection device may be lifted in the front thereof when the heavy cover is swung up and, in the worst case, the draft protection device may tilt back from the upper surface of the balance housing.